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The paper shares an experience in using the Systems Modeling Language (SysML) for the design and formal verification of UAVs. In particular, the paper shows how our approach helps detecting early design errors. A UAV in charge of taking pictures serves as educational and running example throughout the paper. The SysML model of the UAV is simulated and formally verified using the free and open-source tool named TTool. This educational case study gives the authors of the paper an opportunity to draw lessons from teaching SysML.

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System-Theoretic Process Analysis (STPA) is a technique, based on System-Theoretic Accident Model and Process (STAMP), to identify hazardous control actions, loss scenarios, and safety requirements. STPA is considered a rather complex technique and lacks formalism, but there exists a growing interest in using STPA in certifications of safety-critical systems development. SysML is a modeling language for systems engineering. It enables representing models for analysis, design, verification, and validation of systems. In particular, the free software TTool and the model-checker UPPAAL enable formal verification of SysML models. This paper proposes a method that combines STPA and SysML modeling activities in order to allow simulation and formal verification of systems' models. An automatic door system serves as example to illustrate the effectiveness of the proposed approach.

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Use case driven analysis is the corner stone of software and systems modeling in UML and SysML, respectively. Although many books and tutorials have discussed the use of use case diagrams, students and industry practitioners regularly face methodological problems in writing good use cases. This paper defines a methodological assistant that helps designing use case diagrams relying on formalized rules and reuse of previous diagrams. The methodological assistant is implemented in Python. It is interfaced with the free SysML software TTool, and with Cameo Systems Modeler.

Switching from document-centric engineering to Model Based Systems Engineering (MBSE), Systems Engineering (SE) has significantly evolved in terms of standard practices for the design of complex, interdisciplinary systems. MBSE consists in a top-down, model based approach to describe the entire system focusing on different points of view that cover at least structural and behavioral descriptions. Over the past decade, the need to perform an engineering analysis in the early steps of the system's life cycle has opened avenues for joint use of MBSE and Multidisciplinary Design Analysis and Optimization (MDAO). MDAO is fully dedicated to Analysis and Optimization: the model is restricted to a single aspect of the system that is described in details in a formal language that will be the input of the associated computing tool. This paper surveys and categorizes MBSE and MDAO approaches for better understanding of how MBSE and MDAO can be associated in a systems engineering project. Lessons learned from this literature survey will be used in the framework of French project Concorde. One major expected achievement of the project is to design and implement a methodology to populate parts of the MDAO modeling approach directly from the MBSE one, applied to a UAV case study.

Abstract. The paper discusses the use of the TURTLE UML profile to model and verify service continuity during dynamic reconfiguration of embedded software, and space-based telecommunication software in particular. TURTLE extends UML class diagrams with composition operators, and activity diagrams with temporal operators. Translating TURTLE to the formal description technique RT-LOTOS gives the profile a formal semantics and makes it possible to reuse verification techniques implemented by the RTL, the RT-LOTOS toolkit developed at LAAS-CNRS. The paper proposes a modeling and formal validation methodology based on TURTLE and RTL, and discusses its application to a payload software application in charge of an embedded packet switch. The paper demonstrates the benefits of using TURTLE to prove service continuity for dynamic reconfiguration of embedded software.